1. Field of the Invention
The present invention relates to a bracket for attaching a light guide to a frame of a liquid crystal display device.
2. Discussion of the Related Art
Generally, a conventional liquid crystal display (LCD) device includes, as shown in FIGS. 1 and 2A, a liquid crystal panel 20 and a back light attached to a frame 19. The back light includes a fluorescent lamp 11, a U-shaped lamp housing 12 enclosing the fluorescent lamp 11, a light diffusing sheet 18, a first prism 17, a second prism 16, a protecting sheet 15, a light guide 13, and a light reflecting sheet 14, all of which are sequentially assembled onto one side of the liquid crystal panel 20. The back light illuminates a display area 21. The display area 21 includes two transparent substrates (not shown) facing each other and having a liquid crystal between them (not shown), and two polarizing panels (not shown) attached to outer sides of the two transparent substrates. The liquid crystal display device further includes a driver circuit 30 for controlling the display area 21.
FIG. 2A is a plan view showing an assembled structure of the light guide 13 and the frame 19, and FIG. 2B is an enlarged view of part A of FIG. 2A. As shown in FIGS. 2A and 2B, the light guide 13 is attached to the frame 19 by mating a protrusion 40 formed at the light guide 13 with a groove 50 formed in the frame 19.
Referring to FIG. 1, the fluorescent lamp 11 at one side of the light guide 13 is turned on, and light from the fluorescent lamp 11 is reflected by the lamp housing 12 and transmitted to the other side of the light guide 13 (opposite the fluorescent lamp 11) through a cross-section of the light guide 13. The light is spread through an entire body of the light guide 13, and the light is again reflected to the display area 21 by the light diffusing sheet 18.
The liquid crystal display device selectively passes the light by controlling pixels using thin film transistors (TFTs) formed on the liquid crystal panel 20 in response to signals from the driver circuit 30. The liquid crystal display device displays a picture and/or video images on the display area 21 of the liquid crystal panel 20 using the pixels to selectively pass the light.
As shown in FIGS. 1, 2A, and 2B, the fluorescent lamp 11 is assembled on one side of the light guide 13 using the lamp housing 12. The light reflecting sheet 14, the light guide 13, the protecting sheet 15, the prisms 16 and 17, the light diffusing sheet 18 and the lamp housing 12 are attached to the frame 19, which is made of plastic. The light guide 13 has a shape such that a cross-section of a side near the fluorescent lamp 11 is larger than the cross-section of the opposite side. Such a shape helps the light spread through the entire body of the light guide 13 uniformly.
The conventional light guide 13 includes the protrusion 40 for mating with the groove 50 of the frame 19. The light guide 13 is mated to the frame 19 by inserting the protrusion 40 into the groove 50.
As shown in FIG. 2B, the protrusion 40 and the groove 50 are of different sizes, so that a small space 10 must remain between the protrusion 40 and the groove 50, and between the light guide 13 and the frame 19. Therefore, the light guide 13 is not firmly attached to the frame 19 and is subject to impacts due to shaking and chafing. The light guide 13 or the frame 19 can crack and/or break due to the impacts, and small pieces broken off from them can scratch the display area 21.